The present invention relates to projection television systems in which an enlarged television display is produced for viewing. The color television picture tube offers a bright clear display system for viewing television programming. The largest practical color television picture tube has a diagonal dimension of approximately 25 inches. The practical size limitation for a color television picture tube is largely determined by practical size, weight, and cost considerations. Many attempts have been made to produce enlarged projection display systems for displaying television information. These projection television systems vary from a simple optical projection of the output of the conventional television tube to a display screen, which system depends on relatively high cost optical lenses. In such high cost lens systems as the area of the projected display increases, the cost of the projection optics increases dramatically. The most widely used projection television system is one which uses a light valve or diffraction medium associated with the cathode ray tube to control the passage of visible radiation in correspondence with the television set information signals. These diffractive medium displays are very expensive and have a limited lifetime because of the breakdown of the refractive medium in the vacuum environment. A more recent development in a projection television system is a three tube system with each tube generating primary color radiation with a fixed optics system for projecting the output of each of the primary color tubes onto a display screen. The display screen has a lenticular surface for reflecting back the projected image in a narrow beam path. This system is much less expensive than the diffracted medium system but is still relatively expensive and suffers from a relatively low brightness for the display image.
In summary, prior art projection television display systems all suffer from the disadvatage of relatively high cost and low effective image brightness. The prior art projection television systems all utilize an inactive display screen medium.